Adventure at the edge of Civilization.

Noble Ranks of Kingdom of Marthis

King or Queen
Addressed as Your Royal Majesty
Written His or Her Royal Majesty

Regent

Addressed: as Your Highness
Written: His or Her Highness
Unless they are also the Crown Prince or Princess then they are addressed as such. Through some kind of chance the Kingdom of marthis has never endured a long term sickness or madness in a Sovereign, thus the only regencies have been in times of minor children taking the throne.

Crown Prince or Crown Princess
Addressed as Your Royal Highness
Written His or Her Royal Highness
Must be the Age of Majority and formally declared as Heir

Royal Prince or Royal Princess
Addressed as Your Highness
Written His or Her highness

Prince or Princess
Addressed: as Your Highness
Written: His or Her Highness
This is a Ruler of the Princedom, rather than son or daughter of the King. The last princedom in the Kingdom was dissolved after the Robert rebellion.

As a Rule, most Peers also have a House name or family name, this is rarely used by peers when ruling but often is used to refer to Children or unpeered relations. These people are still considered nobles under the law. They may as a courtesy be referred to as Lord or Lady[Forename] of House [House or Family name]

The following are not nobles in the strictest term but generally are seen as such from the Peasants of the Kingdom and often are punished as nobles under the law. Only a noble could judge them as not noble however, if that was the case they be punished as if their were Yeomen. Only in the most vile cases has a Noble done this.

Baronet or Baronetess
Address: Sir or Dame [Forename]
Written: Sir or Dame [Forename] of [Village name]
Only the Crown and dukes can create Baronet, though nobles serving dukes may put for suggestions for new Baronet. Baronets are hereditary knighthoods

House knights
Address: Sir or Dame [Forename]
Written: Sir or Dame [Forename] of [House name]
Nobles are able to dub there own knights that directly serve them. In theory all of these knights are of equal rank under the law.